Automatic transmissions include metal components that rotate and engage with each other during operation. Over time, small metal shavings and pieces (commonly referred to as fines) are produced and contaminate the transmission fluid. The fines can cause damage to the valve body and clog the passageways of the hydraulic circuits if not properly contained.
Most automatic transmissions include a filter typically located in the sump for filtering the fines and other debris from the transmission fluid. The filter media is capable of filtering the fines, but over time, the fines can clog the filter media reducing the service life of the filter. As such, it is advantageous to trap the fines using a magnet or other means.
Many transmissions include a single magnet disposed on the oil pan to trap the fines. The surface area of the oil pan is much greater than that of the magnet and a significant amount of time is required for all of the fluid to pass through the magnet surface boundary so that the fluid born fines can be separated and trapped on the magnet. This slow process presents a significant disadvantage because many fines can freely circulate to the filter media and over time clog the filter. Further, the particle size of some of the fines is small enough to pass through the filter and negatively affect the sensitive electro-hydraulic components of the valve body.
This application discloses an oil filter that solves these and other problems as will be described below in more detail.